Probably because it's tired, but there are a lot of answers to that question.
kill it.
There is no easy way to stop dogs from sniffing each other as this is the way dogs find out information about things. A male dog does not go into heat. Only female dogs do.
That depends on the dog itself, and the dog it may be playing with.
well it depends on the dogs personality... if the dog is friendly and loves to be around other dogs and people then yes. most hyper dogs do. if your dog is aggressive then not always
If your dog is a herding dog, it might be because of that. Herding dogs have behavior of biting sheep on the leg. If your dog is not a herding dog, it might just be playing.
you just keep it indoors all the time
if you think the dog looks nasty then dont walk by it
If the dog is a outside dog just being in the sun running and playing also dogs tend to roll on dead frogs.If a indoor dog then it could be that it just needs a bath.They can also smell from playing with other dogs.
Dogs learn about other dogs through the scent they leave. Similar to when people talk to other people, dogs convey messages through scents. A dog that smells another dogs urine, can learn if that dog is male or female, if they are in heat, what the dog's temperament is, if they are healthy or sick, etc.
Some examples of dogs playing musical instruments include a dog playing the piano, a dog playing the drums, and a dog playing the guitar. These talented dogs showcase their musical abilities in various videos and performances.
Well there are lots of things you can do with just dogs like taking them for walks, playing fetch but you can also do stuff with dogs that you can do with other animals like buying them treats, brushing them, playing various games with them.
Once a dog starts attacking a smaller dog then all the training in the world is not going to help. Dog owners with these types of dogs should put a muzzle on the dog and also keep them on a tight lead. The only place this type of dog should be let run free is an open field where there are no other animals or people around. The problem with some dogs attacking other dogs is they may also attack children or adults. Why some dogs do this and others don't is even a mystery to vets. If another male dog is neutered then generally the other dogs that aren't or even are will leave that dog alone, but, in the case of a dog such as yours that won't even stop them. Trained to listen to your commands or not I wouldn't trust your pet. He/she may be loyal to you, but you can NEVER trust this dog with other dogs or even other people.